The chief (or in his absence his assistants in charge of the fire) shall, after its extinguishment, make a prompt and thorough investigation of the cause of the fire, the time of breaking out, the amount of loss and insurance, a description of the affected buildings and premises, and shall secure all other affected buildings and premises, and shall secure all other useful information and data available and record the same in a record book kept for that purpose in the office of the department and shall report the same to the city council at such times as it may direct. (Prior code §7-17)